The primary aim of the Data Analysis Core is to combine data from all contributing research projects and from the Genotyping Core and to use this information to address the three Program Specific Aims. To achieve this objective the following steps will be performed: 1. A system for data entry and data quality control will be developed and implemented. 2. Program scientists will be assisted in the statistical analysis and interpretation of the results within each of the individual components. 3. New statistical programs in the form of SAS macros will be written and tested. 4. To address Program Specific Aim #1, QTL mapping analysis will be performed on the 600 UM-HET3 mice in population I to identify loci that affect age-sensitive traits within each measurement domain. 5. A similar analysis will identify QTL that affect age-sensitive measures across multiple physiological and biochemical domains. 6. To address Program Specific Aim #2, correlations between age-sensitive traits within and across measurement domains will be studied both with and without adjusting for genetic effects. 7. To address Program Specific Aim #3, age-sensitive outcomes will be compared in two groups of mice (Population 2), one of which has been selected for alleles that are associated with extended life span. This application presents the statistical model that will be used for the QTL mapping as well as a power analysis based upon the currently available genetic map with a set of simulated phenotypes. The sample size-which is based upon budgetary limitation-is adequate to detect approximately 70% of a set of 50 hypothetical Qtls with heritability 0.2 after adjustments for multiple comparison artifacts. Several precautions are described to alleviate the problem of multiple comparisons and to control the overall alpha level.